


Animal Impulses

by DadIWriteGayPorn



Category: Harry Potter - Fandom, Harry Potter - J. K. Rowling
Genre: Age Difference, Anal Sex, Bestiality, Centaurs, Classroom Sex, Consensual Underage Sex, Divination, Ephebophilia, Fucked Up, Gay Sex, Horse cock, Horses, I Can't Believe I Wrote This, I Wrote This Instead of Sleeping, Light Petting, Loss of Virginity, M/M, Oral Sex, Paraphilias, Public Nudity, Public Sex, Student Harry, Taboo, Teacher x Student, Teacher-Student Relationship, Teacher/Student Roleplay, This Is Why We Can't Have Nice Things, Underage Kissing, Why Did I Write This?
Language: English
Status: Completed
Published: 2019-06-14
Updated: 2019-06-14
Packaged: 2020-03-09 12:12:58
Rating: Explicit
Warnings: Underage
Chapters: 1
Words: 5,886
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/18916759
Author URL: https://archiveofourown.org/users/DadIWriteGayPorn/pseuds/DadIWriteGayPorn
Summary: In his new Divination class, Harry gets distracted by his teacher, a Centaur named Firenze. Specifically, Harry is distracted by his surprisingly large package. Harry is even more surprised when, after class, Firenze propositions him





	Animal Impulses

**Author's Note:**

> To readers new to my fics, welcome! To those who read a lot of my fics: I'm so sorry it's been so long since my last proper updates. First I caught a cold, and while that shouldn't keep me from writing it still took up a lot of my time. Then I had to spend the week taking care of a friend's house/pets. While I was there I got my nails done for the first time ever, and that made it damn near impossible to type for several days. Next came an actual vacation where I spent time relaxing with family. So you're overdue for an update. 
> 
> I've had the idea in mind for this for years! In fact, at one point a couple years ago I actually typed it up, but sadly had to delete it before I could post so that my parents wouldn't find it. With the success of my fic Bring Me Back A Dog I decided I give this another whirl. I'm not sure if this will achieve the same level of success since most of the people who read BMBAD were probably only there because they ship Harry/Sirius. But whatever. It's good to get this out of my head. Hope you all enjoy! This took extensive research.
> 
> I now have a tumblr where I post updates and answer questions and post random fandom stuff: https://www.tumblr.com/blog/dad-i-write-gay-porn

IT WAS DISTRACTING, REALLY. Harry could scarce pay attention to anything happening around him, which was a shame considering where he was. It looked like the dead of night in a forest. And yet it was a classroom, in the middle of the day! There were crickets chirping, trees swaying in a gentle breeze, the night sky dotted with thousands of twinkling stars and the Milky Way up above. There was even a campfire that Harry and all the other Gryffindors were gathered around! They were all sitting in the dirt and grass, or upon tree stumps. Some people were even lying on their backs, gazing up at the stars above. 

One could be forgiven for forgetting it was all fake. Just magical trickery to cover up the interior of the classroom. And there were still walls and windows to be seen, but so thorough was the illusion that these faded into the background. But Harry noticed none of it. Sure, he'd been fixated with the breathtaking surroundings on first arriving, just as everyone else had been. But now he could only concentrate on one thing: the new Divination teacher, Firenze. 

And, in truth, Harry could hardly be blamed for having his attention captured by the new teacher as well. That was, if he was _only_ staring at the teacher's form. For Firenze was a Centaur! A half man, half horse. From the waist up he was a human male, handsome in a mysterious sort of way. A chiseled jawline with a hint of a pale beard growing, and a flowing mane white-blond hair and astonishingly blue eyes. His chest and stomach were muscular, if a bit hairy, and there was still the imprint of a hoof on his chest, as though he had been kicked by another Centaur. But below his waist Firenze had the strong pale white body of a fully-grown Palomino!

"You will notice," the Centaur said in a deep and alluring masculine voice, "the brightness of Mars. This signals a coming war, a struggle for power." He pointed up at a beating red dot in the sky, showing off his muscular arms. Most of the class hung onto every word he was saying, but Harry couldn't bring himself to pay attention, so deep was his focus on the Centaur's body. 

It was a sight to see, even to Harry and Ron, who had both seen Centaurs before. But Harry's eyes were set a little too low for simple magical creature curiosity. In fact, ever since he had sat down by the campfire, Harry's eyes had been following one thing. Firenze's penis. 

Well, his whole package. But how could Harry not look? It was massive! The two swinging testicles were each three or four times the size of Harry's fist, easily. Sometimes they would catch the light from the fire and Harry would see thick veins on the sides. And the cock itself! Even soft it was huge. Even in this darkness, this half-light, Harry could tell it would never fit in his mouth. 

The boy blushed hard. _Why did I think that? Why was that the thought that came to mind? Why am I doing any of this?! He's a horse, I shouldn't feel this turned on!_

But Harry's eyes stayed glued to Firenze's package. He shifted uncomfortably, getting hard. This made him blush even darker, and he rubbed his crotch while clenching his muscles, both hoping to feel the friction and to keep his boner unnoticeable. He shot a quick, worried glance around at his fellow classmates to ensure that no one was watching him, then his eyes returned to the Centaur's genitals as he rubbed his crotch. He should have looked at Firenze's eyes. 

 

\------------------------------------------------------------------------------------

 

Firenze was eternally grateful when the school bell finally rang, signaling the end of class. Even among Centaurs Harry Potter was famous. He'd had the honor of meeting the boy a few years prior, too. So, of course, his attention had been drawn to the scar-faced teen the moment he had walked into the classroom. The scent coming off of Harry was tantalizing, and it took strength of mind to keep it from snagging Firenze's focus. And on top of that, he had always been very observant, so the Centaur had noticed _where_ the boy was staring for the entire lesson. 

He had to talk to Harry anyway, but as he watched the boy's desirous looks a plan began to form in Firenze's mind. One that he quickly and compulsively accepted. From that point on it took his deepest concentration and focus not only to continue teaching the class coherently, but to keep himself from growing hard as well. He was almost certain that Harry would accept his proposal. 

And he'd made it! All the students- Fifth Years- were standing up, dusting themselves off, and heading for the door. Some looked startled & bemused, and had clearly forgotten they were still inside Hogwarts. The room filled with light as the door opened and students began to pour out, heading for lunch. 

Firenze waited until most of the class had left before calling out. "Harry Potter." 

Harry, who had been halfway to the door (walking awkwardly with his schoolbag covering his crotch) froze and turned to face the Divination teacher. "Err, yeah?" He said, sounding sheepish. 

"I would like a quick word, if you don't mind?" Firenze paced forward a few steps. Harry's blushing face suddenly turned pale. He clearly thought he was about to be told off for his lustful staring. 

"S-sure!" It came out as a squeak. He shakily waved on his friend, Ron Weasley. Firenze waited until everyone else had left the room and the door had swung shut, returning he and Harry to semi-darkness before speaking. 

"There are two things I wish to discuss with you," he said. Harry seemed to be holding his breath. Firenze took another step closer to the boy. First things first, the Centaur needed to tell Harry what he had planned on telling the boy even before catching his gaze. 

"Firstly, I understand that you are still a friend of Rubeus Hagrid, are you not?" 

Harry's face filled with relief. "Oh! Er, yeah, I am! Why?"

Firenze nodded. "I would like you to deliver a message for me, please. Tell him exactly this: his attempt is not working. He would do better to abandon it. He will know what that means." 

Harry frowned, trying and failing to work out what the message meant. "His attempt isn't working. . . ?" He repeated blankly. 

"And he would do better to abandon it, yes." Firenze nodded again. "I would deliver the message myself, but I cannot have this overheard by anyone else. And as my herd has banished me it would be unwise for me to go to Hagrid's hut, so close to the Black Forest. Hagrid has enough problems without being caught in the middle of a Centaur's quarrel.

"And that brings me to the second issue I have to discuss with you." Firenze allowed himself a small smile and unblocked all the internal walls he had put up during the lesson to keep himself from becoming aroused. He paused momentarily, picking his words. Harry heard his tail swish and realized he was holding his breath again. 

"In my herd I was what you humans call a 'stud,' or a 'stallion.' Do you know what that means?" 

Harry shook his head, still looking curious about the meaning behind the message he had been asked to deliver to Hagrid. Firenze's smile morphed into a smirk. 

"It means that it was my job to breed with as many of my herd's females as I could, as often as I could, with the goal of impregnating them to increase the size of our herd." 

Harry took a sharp gasp, his blush returning. And yet he stayed rooted to the spot even as Firenze took another step forward. He clearly wanted to hear more.

"This means that my body- that _I_ \- am used to a certain level of regular sexual release. Release that has been denied to me since I was cast out of my herd."

"Wh-what's that got t-to do with m-me?" Harry asked shakily, shifting his bag more firmly over his crotch to hide his boner. Firenze had nothing to cover himself as he began to slowly stiffen, his cock unfurling. But for once Harry's eyes were glued to the Centaur's face, and he missed the show. 

"I have talked with Professor Trelawny about her students. I have seen your grades. You will not be able to pass this class without help, that is very apparent to me. So I have a proposition for you. One that I inquire you to hear out fully before saying anything or making any decisions." Firenze pawed fretfully at the ground, but Harry was too horny to take notice.

"I want you to help me get that sexual release I am missing. Only once every week, or more often if you so choose; I am actually accustomed to daily release, but understand that that may not work for you. In exchange, I will not only ensure that you pass this class, but I will also allow you to act out your sexual desires on me. After mine are met, of course." Firenze fell silent. 

Harry tried to act disgusted and offended. He knew it was what he was supposed to do. But he wasn't even convincing to himself. 

"What?! Why. . . Why do you think I'd want that?! That's gross! I'm 15, you're a teacher and. . . And a horse! It's wrong! It's. . . ." Harry was unable to find a suitable word. Firenze laughed. 

"Harry Potter, I know you have an erection right now. And I can smell the sex and hormones coming off you in waves like a mare in heat. _And_ I saw you staring all through the lesson. Do not try to hide it, I know you want this. It is alright. No one need ever know." His voice was calm and inviting, if also provocative. 

If Harry's face grew any redder it would become indistinguishable from a Quaffle. "B-but. . . Acting out my sexual desires on you?"

Firenze nodded. "My rear should be sufficient. I've taken all the necessary precautions and measures to ensure it is a clean and smooth experience for you." 

The boy's resolve was breaking before Firenze's eyes. Harry knew it was wrong, but how was a teenage boy in the throes of his new sexuality supposed to turn down an offer like that?

"What. . . What do I do, exactly?" 

"Nothing hurtful," Firenze promised. "Touch me, lick me, make me feel you where you are not supposed to be. I will do the rest. I am pent up enough that it should not take much." His tone sounded bitter, but a warm, and propositing smile played at his lips, comforting Harry's wired nerves. The boy took a small step forward, looking hesitant. He was only a couple of feet away from the Centaur now. 

Harry slowly stretched out a hand, reaching forward. He paused momentarily, looking into the Divination teacher's face. But Firenze inclined his head in what was clearly a respectful nod of permission, and Harry reached the rest of the way to press his hand against Firenze's waist where white fur and experienced skin blended together. Firenze closed his eyes at Harry's touch, enjoying the feel. 

From across the makeshift classroom, the horse hair had looked soft. And to some degree it was, but it was also much more coarse and rough than Harry had expected. More like bristles than fur. It was Harry's first time ever touching a horse. Well, he had actually ridden on Firenze's back his first year at Hogwarts, but it had been just after narrowly escaping from Lord Voldemort in the Forbidden Forest. Harry hadn't been paying any attention to how the Centaur's fur felt then. 

Still, even though it felt coarse, Harry liked the feeling. It was warm and alive. Harry's hand shifted upward, feeling up his smoother (though still hair-covered) stomach. His eyes moved to Firenze's sculpted, muscular chest, taking in everything and lingering on that hoofprint. He made his decision then. 

"I'll do it!" 

Firenze's eyes opened serenely. His smile widened, showing surprisingly perfect white teeth. "I am pleased, Harry Potter." He dipped his head respectfully again. 

"When. . . When do you want me to start?" Harry pulled his hand back and rubbed his crotch. 

Firenze cocked an eyebrow. "Well, I was thinking we could begin now. You are on a mealtime break, are you not?"

Harry couldn't help but show an eager grin. He nodded excitedly and swung his schoolbag off his shoulder, dropping it onto the earthy ground. "I was hoping you'd say that!" He tried to sound confident, but his cheeks were flushed and his voice was a little too high. The boy was clearly flustered. It was his first sexual experience outside of his hand, and it was with a _horse!_

But Harry was also obviously thankful for this opportunity. He was still wrapping his mind around all that was happening and all that was about to happen, but he was too horny to turn Firenze down. And he honestly wanted this at least as badly as Firenze did! Harry wasn't sure what it was about this Centaur and his anatomy that attracted him, but he was eager to get his hands dirty. 

Harry began to drop down, intending to crawl under the Centaur, but Firenze held up a hand and stopped him. "Ahh, wait for a moment, Harry. I was thinking that perhaps this was something you should do naked, unburdened by your robes?" 

Harry stopped, then straightened back up, blushing. "Oh! Oh, yeah, right!" He chewed on his bottom lip a moment, then started kicking off his shoes. "Err, so. . . I'm just wondering," Harry used his toes to pull off his socks (a mismatched pair, one bright red and patterned with broomsticks and the other green with Snitches, that Dobby the House Elf had gifted him), "why did you choose me? Why not Lavender or Parvati? They seem like they'd do anything for you. They seemed attracted to you too! Called you 'gorgeous.'" 

Firenze chuckled as Harry began to pull his robes off over his head. "There are a number of reasons. For one thing, they are not nearly as good-looking as you are, Harry." He winked and the teen blushed as his robes fell in a crumpled heap on the ground. He was left in only his underwear, a pair of plain black boxer-briefs with a defined tent. 

"For another," Firenze continued, "I cannot risk getting one of them pregnant. That may have been my duty in my herd, but planting my seed in an underage witch would cause many complications for both of us."

Harry nearly choked, and a vivid image of a pregnant Lavender Brown entered his head. "But. . . Hang on. Horses and humans aren't sexually compatible when it comes to mating," Harry scowled. "I may not know a lot about horses, or any of this really, but I do know that much!"

Firenze chuckled again, his cock twitching beneath him. "If I were simply a horse then that would be true. But Centaurs are also half human. And, in any case, where magic is involved almost anything is possible. There are several documented cases in the last three centuries of Human/Centaur offspring. I believe there are even rumors about one of the members of a band known as The Weird Sisters. . . .

"But come, now. Lunchtime will be over soon. It is time for us to begin. If you would be so kind as to remove that last article of clothing?" 

Harry hesitated. He still very much wanted to do as Firenze had proposed, but he was starting to feel embarrassed. He remembered how big the Centaur's genitals had been even flaccid. Harry's normal teenage feelings of inadequacy were already bad enough without bringing someone truly hung like a horse into the mix. 

Firenze seemed to read his mind. He smiled and reached a hand out, touching Harry's face gently. His fingers felt warm and surprisingly soft for someone who spent most  
Of his time in the woods, handling a bow. "It is alright, Harry Potter. I am certain you will be very pleasing to me. You already are."

This was the push Harry needed. He slid his fingers under the waistband of his underwear and began to slide them down, revealing himself fully to his teacher. Firenze kept his face impassive, but inside his heart was pounding. Much the way Harry clearly felt about him, he had always had something of an unusual fascination with human male anatomy. 

Harry's figure was slim. He had some muscles for sure, but nothing that was clearly defined. But Firenze wasn't focused on all that. His eyes slid lower, to the boy's crotch. Harry had a solid hard-on. His cock, rather thick for a boy his age, pointed directly outward. Bluish veins could be seen beneath smooth, pale skin. He had quite a lot of thick black hair growing just above the base of his shaft, and Harry's foreskin was long and full, covering most of his purple cock head, which was already dripping with fluid. All in all, he was at least six inches. Firenze liked what he saw. 

"You had best get to work, Harry Potter," he licked his lips, eager to finally relieve himself. Harry, shivering a bit, sank immediately to his knees and crawled beneath the Centaur, choosing to act before he could think about anything he was doing. And at last he came face to face with Firenze's fully-erect cock. 

"Big" wasn't a word that did Firenze justice. His shaft alone was as long as Harry's arm, only much thicker. While nearly all of Firenze's body was a white-gold shade of blond, his cock stepped away from that pallet. It was mostly a dark brown and black color with a couple wide splotches of white here and there. One such splotch closest to the Centaur's head was roughly the shape of a diamond. There was a ring of flesh wrapped around the center of Firenze's shaft, too, that Harry was curious about. 

"Touch me, Harry," the Centaur moaned in a strained voice. Harry didn't need to be told a second time. The boy reached out with a surprisingly even hand and wrapped it around Firenze's cock just below the head. The Centaur groaned deeply and scuffed the ground with his hoof. 

Harry marveled at the feel of the equine cock in his hand. He reached with his other hand to firmly grasp the horse closer to its base and heard Firenze gasp more. The teen's knees became smeared with dirt as he edged closer, putting his face mere inches away from the massive member in order to truly take everything in. 

It was surprisingly leathery. Not smooth and fleshy like a human penis, but much more solid and gripping. The head of Firenze's cock was also vastly different from a human's. Its corona, while still vaguely circular, was oriented much differently from a human. The head was flared out, rather than coming down and ending in somewhat of a point like Harry's penis. Firenze's cock head was rounded out almost flatly, save for a wide circular divot or pit towards the bottom of the head, from which a sort of shallow tube was protruding. This was clearly where the horse's piss and cum came out of. The head itself was very uneven and bumpy. Harry ran his fingers over it slowly, feeling it up. 

Firenze let out a high moan that sounded almost like a neigh. Harry rubbed it more. Firenze's cock started to twitch up and down in Harry's grasp, forcing the boy to hold on tighter. He could smell the cock in his face. It was the smell of sweaty balls and barnyard animals mixed into one. An odd combination for sure, but one that turned Harry on even more. He leaned closer still, head rising and falling with the convulsive, rhythmic twitches of Firenze's dick. Harry took a deep breath before breaking what remained of his inhibitions completely, leaning the rest of the way in and beginning to lick the head. 

Firenze moaned his loudest yet. Harry could hear him huffing and grinned, licking harder now, less tentatively. The horny boy had expected some alien flavor to hit him when he started licking, but mostly he just tasted sweat. It was a strong taste for sure, but not altogether unappealing. Harry kept licking, letting his hands slide freely up and down Firenze cock shaft as it continued to twitch and throb. Occasionally he would reach all the way back and grab one of the horse's massive testicles teasingly. 

_I'm sucking a horse cock! I'm feeling a horse cock! And. . . He's gonna cum on me! Maybe in my mouth..._ Harry shuddered. He felt a dark warmth spread through his body from his heart as a fresh wave of horniness made him feel light headed. He stopped licking around the outer parts of Firenze's head and moved instead to the tube-like protuberance he had noted earlier. 

Harry's tongue wrapped around the tube and he started slipping the tip inside the horse's cock hole. **Now** Harry could taste Firenze's piss! It was strong and unpleasant, yet Harry couldn't make himself stop licking. He didn't want to. There was another flavor there as well, this one much more enjoyable. Harry assumed it must be old semen, but as he'd never even tasted himself he wasn't entirely sure. Still, he was much too horny and much too far along to stop there. He licked harder. 

Firenze knickered in appreciation and closed his eyes. He hadn't been lying earlier when he had told Harry it wouldn't take much to bring him to orgasm. He was so pent up that already he was growing close. He knew he could have felt that release sooner. He _was_ capable of masturbating; in fact, that was what he was doing which caused his cock to twitch up and down in Harry's grasp this very moment as the boy licked him. He was pleasing himself. But the physical aspect, the sense of feeling someone else touching him, was a link that he enjoyed as much as the orgasms themselves. Without that he would never come close to the same levels of release he had grown used to and which he desired. And honestly, the thrill of having Harry Potter, an underage famous human boy do this to him brought him more of a thrill than simply breeding another female in his herd would have. It didn't matter that there was no penetration. 

Harry's arousal kept growing. Every lick, every squeeze of his hands and caress with his fingertips against Firenze's cock drilled the wrongness of what was happening deeper and deeper into the boy's skull. And he liked it. Soon Harry was moaning freely and loudly, not from any pleasure, but from the wrongness of it all. Even as he made Firenze's massive cock head slick with his saliva, Harry began daydreaming about what was to come next. Harry himself was able to unload an impressive amount when he came. But everything about Firenze dwarfed Harry in size. He could imagine how much more semen the horse would produce. He tightened his grip on the bouncing horse dick. 

Firenze didn't normally sweat during sex. It was running through the Black Forest, and then the Hogwarts grounds that generated the sweat Harry could taste. With breeding the females in his herd it was normally a quick activity, more his duty than anything truly rambunctious. It was always mount, thrust a couple dozen times, ejaculate, dismount, move on. But this was something else entirely. As this was taking more time, and because he was so pent up, Firenze could feel everything! And since the smallest of Harry's touches sent spikes of pleasure shooting through his body, making him pant and gasp and neigh, Firenze had begun to sweat. He wanted it to last longer, to keep going well after the end of lunch bell rang. But he was already extremely close to the edge, to his orgasm. Besides, that wouldn't be very fair to Harry. 

Harry's tongue kept slipping inside Firenze's cockhole. Whenever he did this, Firenze would let out a loud choked moan. These sounds wreaked havoc on Harry's self-control. It took all the willpower he could muster to not pound off while he was blowing the Centaur. He needed the use of both hands for this. Harry could see and feel the Centaur's balls shifting and contracting, preparing to blow a load. 

Harry trailed his fingertips lightly up and down Firenze's shaft, trying to ease him closer to cumming. He still couldn't believe just how big Firenze was! His cock was so thick that Harry couldn't fully wrap his hand (or head) around it. Firenze groaned loudly and pawed at the ground again. 

"P-prepare yourself, boy!"

Harry watched with held breath as the head of the Centaur's cock began to flare out and expand, growing somehow harder than it had already been. The tube within the head seemed to stretch out, cockhole growing wide. Harry quickly opened his mouth wide and stretched out his tongue. He wasn't a moment too late. The cock convulsed and began to shoot out a massive load!

The first two bursts fired out a mostly clear, thin yet sticky liquid that reminded Harry of his own precum. The next shots were much more reminiscent of the teen's own money shots, pearly and thick. Harry's face and chest caught most of the stuff. It spattered all over with surprising force. Harry had to close his eyes despite his glasses to avoid getting the cum in them. It completely covered his face like some kind of hot, creamy mask. It stuck in his hair and filled his mouth. 

The taste was completely foreign to Harry. Though he'd masturbated many times, he'd never yet had the courage to taste himself. He was pretty sure he would taste different than this horse, in any case. But Firenze's flavor was far from unappealing. It was strong, yet not overwhelming. Not exactly sweet, but miles from bitter. Harry swallowed slowly as Firenze shot again, this time with less force. The load, somewhat gel-like this time, spilled onto Harry's stomach and dripped onto his crotch. 

And then just like that Firenze was done! Harry hastily wiped his glasses clean with his fingers, then popped the fingers into his mouth as he watched the Divination teacher's dick deflate and shrink quickly back into its sheathed state. 

Harry's head spun as the headrush that had accompanied Firenze's orgasm dwindled away. _What the hell did I just do?_

Firenze's tail swished to the side and Harry heard the Centaur's deep voice speak. "Thank you, Harry Potter. That was exactly what I needed. You have no idea how much this means to me. Please, come out from beneath me. I want to see you before we complete our deal." 

"C-complete our deal?" Harry squeaked. He could still feel the cum clinging to his lips and face as he spoke. Harry licked his lips nervously, tasting more of the Centaur. 

"Yes, Harry. We agreed that you would relieve yourself into my rear, remember?" The man's voice was gentle and patient. 

"Oh! Right!" Harry had forgotten about this part of their agreement, but Firenze's reminder relit his lustful fire, pulling him away from bashfulness. Harry slowly crawled out from under the Horse's body, straightened up, and displayed himself. 

Harry was standing with his fists at his sides, letting Firenze see all of him. His cock was standing up proudly, and he was practically covered in the Centaur's seed. It matted his black hair, dripped off his chin, and slid down his hard nipples. 

"Come here, boy," Firenze turned to face Harry more directly and held out a hand. Harry stepped forward obediently, and Firenze took the boy's face in his hand. He held him tightly, cheek to chin, and tilted his head up, forcing eye contact. 

"Did you like that?"

Harry nodded as best he could, heart pumping furiously. 

"So did I. Do you want to keep doing this for me?" 

Harry nodded again and Firenze released his face. "Good. Now, let us go uphold your end of our bargain. Follow me. You are much too short to reach properly. Something must be done to accommodate you." 

Firenze began to strut over to the area where he had been teaching class fifteen minutes earlier, leading Harry. He gestured at one of the tree stumps the students had used as chairs and Harry understood immediately. He stepped barefoot up onto it, raising him up by a couple of feet and bringing his crotch up even with the Centaur's rear. 

Firenze smirked, then turned to present his ass to the boy. "You will have to hold my tail for me, Harry," Firenze chuckled lightly. "It seems to have a mind of its own." 

Harry gulped and reached slowly forward to grab the Centaur's Palomino tail and shift it aside. The tail hair felt softer than the rest of Firenze' body. 

And then Harry laid eyes on Firenze's tail hole. It was fat, black, and puckering. It was immediately clear to Harry that he wouldn't need any lube to fit inside. If he wanted, he was sure he would have been able to fit a fist in there!

Jolted by this thought, Harry's free hand automatically stretched out and he trailed his fingers lightly over the asshole. Firenze closed his eyes and sighed gently. 

Harry was glad to find that Firenze had indeed taken the time to prepare himself for Harry. The teen couldn't stop looking. There wasn't so much as a speckle of dirt besmirching the ring of muscle. 

"Harry, lunchtime will be over soon," Firenze cautioned. "Best get on with it."

"R-right!" Harry said, pulling his hand back and wrapping it instead around the base of his shaft and pulled the foreskin back off his head. "Sorry." 

He took a step forward to the very edge of the tree stump and pressed his cockhead against the Horse's entrance. Harry could feel Firenze's tail trying to swish in his hand and held it down aside tighter. _Here goes nothing! Losing my virginity. . . To a horse._ Harry took a deep breath, steeling himself, then drove his hips forward. 

His cock slid inside the Centaur's asshole like a dream. Despite being much looser than a human's butt, Firenze's gripped Harry comfortably and hit all the right nerves. Harry breathed a deep sigh as he watched his shaft disappear up inside. He was so unbelievably horny that he knew he wouldn't last long. 

"Does that feel good, Harry Potter?"

"Oh God yes!" Harry breathed, sounding flustered. He started thrusting hard in and out. The horse's hole made a wet noise as the student's cock disappeared inside it. _I'm. . . I'm  
Doing it! I'm fucking a horse! And he feels. . . **incredible!** _

Harry's eyelids fluttered as he thrust in as deep and as hard as he could. When Harry's cock pulled back his shaft would be slick, coated in pre and natural lubricants. His moans grew louder with each thrust. All the crickets in the dark classroom fell silent. 

Firenze had fallen silent as well, not giving off so much as a grunt when Harry thrust in and out. And why should he? His insides were much bigger than Harry's dick. And Harry didn't need the Centaur to make any noise to brink him to orgasm, anyway. The fact that he was fucking a teacher, an adult, a horse… it's already more than enough. 

Harry felt the buildup in his gut. Though he'd only thrust a couple dozen times he was already arriving at his completion. The boy gripped the base of Firenze's tail more firmly and forced himself to watch as his maturing shaft disappeared inside the horse's asshole. Harry's breathing grew more intense, labored. 

"Ohhhh God, I'm g-gonna-"

"Do it, Harry Potter," Firenze whispered, looking over his shoulder at the naked teen fucking him. "Complete our agreement. Ruin inside of me." 

Harry thrust harder three more times and then could take no more. He opened his mouth to cry out but found he could make no sound. His cum shot forth inside the horse's ass, and he felt his legs grow weak & powerless, threatening to spill him off the tree stump. Harry held onto Firenze's tail tightly as he unloaded himself, pulling on it slightly. The Divination teacher shot him a look but said nothing. 

Harry couldn't say how long his orgasm lasted. It could have been only a few seconds, or it could have been much longer. But when it passed he was left light-headed and energy-sapped. He pulled his cock out and stumbled off the tree stump and onto his hands and knees in the dirt by the clothes he'd removed earlier. Firenze turned around to look at him. 

The school bell rang. 

Harry's heart nearly jumped our if his chest. He'd missed lunch! Ron and Hermione would be worried. What was more, he only had a couple of minutes before Firenze's next class would be walking through the door! 

"You are covered in my seed and with dirt, Harry Potter," Firenze observed from above him. "It would be best for you to remove it and dress quickly."

Harry panted hard and fumbled through his robes, looking for his wand, and said nothing. He found it and stood shakily, legs crossed with embarrassment now that the horniness had passed, and pointed the trusty holly wand at himself. 

"S-Scourgify!" He stammered. "Tergeo!" All the horse cum and grime vanished off him, leaving his body clean and free of even a drop if semen or a speck of dirt. Harry barely gave himself time to admire his work before diving for his socks, underwear, shoes, and (most importantly) his robes. Firenze continued to watch, tail swishing with almost no worry as Harry scrambled to pull on all of his clothes. 

The boy almost didn't make it. He couldn't find one of the armholes in his robes at first, and danced around momentarily with his top half wrapped up, bottom half exposed. It was an amusing sight, even to the Centaur, who didn't bother to swallow back his chuckles. But at last Harry pulled the robes firmly on, just as the door to the classroom swung open, and many chattering third-years stepped inside. 

"Go now, Harry Potter," Firenze said, blue eyes twinkling at the edge of a smirk. "Your friends will be searching for you, and it would not do for you to be late for your next lesson. I will send word the next time I have need of you."

Harry gave a respectful nod, then turned to push through the crowd of now silent and awestruck third-years just inside the door. He hurried through the halls, heading for the dreaded Defense Against The Dark Arts class to find his two best friends. As he went he thought of various lies to explain away his absence at lunch. He would have to do a lot of talking.

**Author's Note:**

> There you have it. Took nearly a month and a half to write, mainly because of research, but also due to everything getting in the way. I hope you enjoyed reading this. I know some of you will be disappointed that Harry didn't get fucked. I refer you to the chapter 1 notes of my Harry/Padfoot fic Bring Me Back A Dog for the reason why that was left out. If you loved/hated this fic, have criticism (constructive or non), wanna geek out or request future fics and/or pairings, please leave a comment! I wanna hear all feedback, and I reply to nearly every comment
> 
> I now have a tumblr where I post updates and answer questions and post random fandom stuff: https://www.tumblr.com/blog/dad-i-write-gay-porn
> 
>  
> 
> https://www.youtube.com/watch?v=kmFM4S21Cjw


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